1. Field of the Invention:
This invention relates in general to quick disconnect couplings, and in particular to a coupling for subsea flowlines that has valves in each connection and which close when the coupling is released.
2. Description of the Prior Art:
In floating platform subsea well production operations, fluids produced from the well flow under pressure through a riser to a floating production platform at the surface. Also, pressurized fluids are delivered from the floating vessel at the surface through the riser to the subsea well for various control and monitoring purposes. In floating production, there is always the possibility of a voluntary or involuntary move of location, due to, for example, ship or iceberg collision aviodance, anchor dragging or line breaking and severe storms. Quick disconnect couplings have been mounted to the vessels in the past to quickly disconnect the floating production facility from its flowlines, if the need arises, while avoiding the spillage of any well fluids. In these devices, valves are hydraulically actuated to close the lower coupling and the upper coupling in such circumstance.
While successful, the valves and hydraulic controls associated with the coupling make it expensive. Also, there is a fairly long distance between the upper and lower valves, which results in the fluid located between the valves spilling when the coupling is disconnected.